percpu: remove PER_CPU_DEF_ATTRIBUTES macro

The macro is not used:

  $ grep -r PER_CPU_DEF_ATTRIBUTES
  include/linux/percpu-defs.h:	__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak		\
  include/linux/percpu-defs.h:	__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES		\
  include/asm-generic/percpu.h:#ifndef PER_CPU_DEF_ATTRIBUTES
  include/asm-generic/percpu.h:#define PER_CPU_DEF_ATTRIBUTES

It was added with b01e8dc34379 ("alpha: fix percpu build breakage") and
removed in 2009 with b01e8dc34379..6088464cf1ae.

Link: http://lkml.kernel.org/r/20180821164904.qqhcduimjznods66@K55DR.localdomain
Signed-off-by: Alexander Pateenok <pateenoc@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/percpu.h

@@ -62,10 +62,6 @@ extern void setup_per_cpu_areas(void);
 #define PER_CPU_ATTRIBUTES
 #endif
 
-#ifndef PER_CPU_DEF_ATTRIBUTES
-#define PER_CPU_DEF_ATTRIBUTES
-#endif
-
 #define raw_cpu_generic_read(pcp)					\
 ({									\
 	*raw_cpu_ptr(&(pcp));						\

include/linux/percpu-defs.h

@@ -91,8 +91,7 @@
 	extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name;		\
 	__PCPU_DUMMY_ATTRS char __pcpu_unique_##name;			\
 	extern __PCPU_ATTRS(sec) __typeof__(type) name;			\
-	__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak			\
-	__typeof__(type) name
+	__PCPU_ATTRS(sec) __weak __typeof__(type) name
 #else
 /*
  * Normal declaration and definition macros.
@@ -101,8 +100,7 @@
 	extern __PCPU_ATTRS(sec) __typeof__(type) name
 
 #define DEFINE_PER_CPU_SECTION(type, name, sec)				\
-	__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES			\
-	__typeof__(type) name
+	__PCPU_ATTRS(sec) __typeof__(type) name
 #endif
 
 /*